The present invention relates to an apparatus and its method of operation for mounting and spacing a plurality of tool holders along a main beam spanning a work table and, more particularly, to an apparatus and method for automatically spacing the tools in an operative position and for returning the tools to an inoperative stowed position completely outside the work space on the work table.
Non-contact tools, such as oxyfuel or plasma cutting torches, are used in a variety of applications where a plurality of tools are mounted to a carriage for movement relative to a work piece to be operated upon. In particular, cutting torches are used to cut a variety of sizes and shapes from a metal plate. The plate is generally supported on a work table and a bank of cutting torches is supported by a main overhead beam which, in turn, is attached to a carriage for programmed cutting movement over the plate supported on the work table. A plurality of cutting torch holders is typically used so that multiple identical pieces may be cut simultaneously with the torches positioned in spaced relation along the main beam and across the full width of the work table. The number of pieces cut from a plate in any one operation varies and, when fewer than all of the cutting torches are needed, those not being used are stowed in an inoperative position on one end of the beam. Inoperative torch holders which are stored at one end of the main beam either continue to occupy space above the work table, thereby decreasing the effective work space available, or require an extended main beam so that the unused torches may be stored laterally outside of the work space. In the latter case, extension of the main beam merely to provide additional storage space and to preserve full usable work space is both costly and requires additional floor space.
U.S. Pat. No. 3,591,157 shows a system for automatic programmed spacing of multiple cutting torches in which the torches are mounted on a laterally reciprocable control bar which is driven by a programmed master carriage offset to one side of the cutting table. The cutting torches are alternately clamped to and released from a stationary bar parallel to the control bar and the control bar itself to allow initial programmed spacing of the torches and to then allow the cutting torches to follow the cutting pattern in unison. A substantial portion of the cutting apparatus extends far beyond one lateral edge of the cutting table and any unused stored torch holders would be positioned over the cutting table.
U.S. Pat. No. 4,132,392 shows a multi-torch cutting system which utilizes a separate torch bar mounted parallel to the main beam for movement therealong, which torch bar carries the multiple torch heads for selectively positionable spacing along the bar. A master carriage is drivingly attached to the main beam and may be selectively clamped to the torch bar to carry the torch bar and attached torch holders along the main beam, or unclamped from the torch bar so that movement of the carriage along the main beam may be utilized to sequentially engage torch holders which are unclamped from the torch bar to stack them on one end thereof for storage. The torch holders and master carriage are manually clamped to and unclamped from the torch bar and no mechanism for providing programmed torch spacing is shown.
U.S. Pat. No. 4,372,538 shows a multi-torch cutting system in which one torch carriage comprises a master carriage to which is attached the ends of a continuous positioning band which is trained around idler pulleys on opposite ends of the main beam. Movement of the master carriage along the main beam carries the band therewith and the remaining torch holders may be selectively and sequentially clamped to the moving band to establish a desirable variable torch spacing. Unused inoperative torches may be stored at one end of the main beam, but they would be positioned above the work table and prevent movement of any remaining operating torches over the work table in this area.